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[utervo]

I'm doing a Funder Chimp 5F1 amp as my first build. I have some questions regarding the types of resistors, condensators and transformers.

Transformers:
For the power tranny I am planning to use a Finnish made one with the following specs: 230V//300-0-55-300 0,1A / 6,3V 4A / 5V 2A, does that sound like enough?

For output I've thought of using Hammond 125BSE which is for 5W, I wonder how much difference would it make to use the 125ASE which is 3W?

http://www.hammondmfg.com/125SE.htm

Resistors:
I'd like to know are there any "key resistors" in 5F1 where the type of resistor makes the most difference in sound, to be more specific I'm thinking of some spots were carbon comps would be appropriate? I've thought of using metalfilm elsewhere except the 10k and 22k on the psu which I though metal-oxide would suit?

Condensators:
What do you guys recommend for caps? I've though ot Mallory 150's for those two 0,022uF, are there any other "key caps"?

Case:
Does using steel or aluminun have an effect on sound?

Thanks.

[d2camero]

Not sure if you have selected a speaker, but weber makes a nice 8" alnico that sounds terrific with the champ.

I used the fender transformers from hoffman. As long as your PT specs match the original you are good to go. Not too sure about the hammond OT, I have never really liked hammond for OTs (personal preference though).

Malloy 150 metalized polyester caps for coupling and tone.

Sprague atom or Nichicon ecaps.

Carbon comps work best under high voltage, so the plate the place for them. Metal film for anywhere the signal passes through (e.g. grid resistors) and CF for all the rest.

d2

[Bob-I]

You left this open for lots of opinions

I agree about the OT, use the Hoffman or Mojotone, hammond's are fine but if you shoose this route stay with the 5W.

The coupling caps I prefer Orange Drops PS600 series to the Mallory for Fender type amps.

The resistors, I'd go with 1 Watt carbon comp for tone and stability.

I agree with the Weber speaker, I put one in my friends SF Champ and the results were amazing.

Good luck with the project.

[CaseyJones]

The 5F1 is a circuit you can build with just about whatever you have and it will sound o.k..

I've build them with underrated carbon film resistors back before I knew better, it didn't seem to make much of a difference.

A 3 watt OT should work fine, it depends on what you want for tone. A constant forum topic is "how do I get more clean headroom from my Champ", if you want clean build a different amp although a bigger OT helps.

The speaker you want is the Weber SigS. The ceramic version is an upgrade from the desirable early '60s Jensen C8R. The best setting on a Champ IMHO is dimed and it sounds a little more crisp through a Weber Sig.

Bigger is better. These sound great through a 12" speaker, if you want the World's Biggest Champ re-wire a Marshall 4 x 12" to 4 ohms and use that. Use the Sig because it's the best speaker in the stock cabinet and it will give you an authentic Screaming Tweed tone, go bigger if you want it to sound bigger.

The 5Y3 rectifier is limited as to what it wants to "see" for filters. The stock 8 microfarad caps are ridiculous, use 22 microfarads each for all three. Go no larger than 22 microfarads with a 5Y3 rectifier. In theory a 5AR4 will work with the 2 amp / 5 volt filament winding, in practice a 5AR4 may blow the fuse on a stock Champ. I like to have 3 amps available on the rectifier winding so I can use anything for a rectifier. If you use a 5AR4 and never go back to a 5Y3 you can use up to 50 microfarads for the first filter cap.

There are errors in the commonly available original Fender layout. The 1.5k cathode resistor on the first preamp stage is usually bypassed with a 25/25 cap on most original tweeds. The unused lug on the volume pot should connect to ground as per the 5E1 layout, your Champ will do some very screwy things if that isn't grounded.

Ignore the stock values on the 6V6 cathode bypass cap, bigger is better up to a point. 50 microfarads / 50 volts is good, 100 microfarads / 50 volts is better.

You can drop the stock 1.5k first stage cathode resistor to 1k or 820 ohms. You can also re-balance the gain by increasing the second stage cathode resistor to 2.2k or 2.7k.

The 12AX7 plate resistors don't have to be 100k, 220k or 270k can be used.

[Funkalicousgroove]

IMHO the ONLY caps that go in a tweed are Paper-in-oil type, orange drops of all types get harsh, strident, and buzzy when you crank the amp up, POI caps stay smooth and breathy.

As far as resistors, I'd probably shy away from metal film, and either use Carbon Film or Carbon comp. I find that MEtal film can make tweeds sound kinda anemic.

[CaseyJones]

IMHO the ONLY caps that go in a tweed are Paper-in-oil type, orange drops of all types get harsh, strident, and buzzy when you crank the amp up, POI caps stay smooth and breathy.

Yeah, right. Tell you what... I have ten bottles left from a full a case of Chateau Lafite '40-something, next time I open one I'll let you sniff the cork!

Refer back to the comment in the Lead II thread about Randy Rhoads' tone with Ozzy:

I loved early VH, Ozzy, Sabbath, Yngwie and lots of other 'metal bands' of the late 70s and early 80s...and let's face it...some of the early metal tones were pretty bad (eg - as much as I LOVE Randy's playing...his tone on the early Ozzy records was pretty harsh and buzzy).

Indeed, using a Distortion + as an overdrive on an already overdriven Marshall is the polar opposite of "smooth and breathy", you can hear the thing spiral out of control every time Randy take his hands off it. I'd hate to be the poor bastard who had to clean the tracks to make that work.

Speaking of poor bastards... I'd hate to be the guy who has to track down .022 PIOs for less than ten bucks each although if the guy is using a Finnish transformer he can send a few bucks to Lithuania and buy Russian PIOs for cheap.

[utervo]

As for the speaker I've been thinking for a 10" Tone Tubby Alnico or would 12" work. I want to do a separate pine cabin for it so I can use it with something else if needed.

[Funkalicousgroove]

I see russian and Brazillian PIO's for a couple bucks a piece, and since I am such a fine fellow, and a 5f1 only has 2 caps, I'd be happy to send them free of charge if utervo wants to send me a PM with his info. BTW, if you're taking the time and going to the expense of building an amp, why do it half-assed?

Just because you can doesn't mean you should.


FYI, Mojo vitamin T (Brazillian manu.)PIO caps are all $4 or less.

And if you're breakin out that '40-something Chateau Lafite count me in for more than a cork sniff!

[blinddog]

Hi Funk,

Have you finished that Deluxe you were talking about with the PIO's? How is it sounding? I have been following your discussions on these PIO caps for a while now. IF I read right you were just using PIO for the coupling caps, right?

Now being a relative newb, I think the coupling caps are rated for the lower voltages, 25V verses 450V am I reading this right? Deluxe and Champ circuits.

The Brazillian ones seem to be rated at +450V, but prior to those being discussed I was looking at Jensens and those made a big difference in price when the voltage went up. That is why I am checking.

Also if only the coupling are PIO would you mind sharing what you are using for the other Sprauge Atom? Illinois?

Thanks,
B-dog

[CaseyJones]

I see russian and Brazillian PIO's for a couple bucks a piece, and since I am such a fine fellow, and a 5f1 only has 2 caps, I'd be happy to send them free of charge if utervo wants to send me a PM with his info. BTW, if you're taking the time and going to the expense of building an amp, why do it half-assed?

Just because the amp doesn't use super duper high end parts like silver wire, silver solder, NOS tubes with gold pins (cryo treat 'em while you're at it! ), heck, just run down the list of top shelf parts then hook it up to your speaker with that "O" guage Monster Cable (with gold plated ends )... doesn't make it a P.O.S.. A Champ was a low buck lo fi amp originally built with inexpensive parts. Near as I can tell more builds fall down because the builder gets hung up on sourcing high end parts than amps get built with high end parts.

Oh yeah, what's-his-face is probably in Europe (note the 230 volt primary on the transformer) so those PIOs are going to cost you more to ship than you paid for 'em.

Just because you can doesn't mean you should.

Perhaps not but why not do the baseline build with WHATEVER, get it DONE, up and rockin' then build the next one with the "good stuff"?!

FYI, Mojo vitamin T (Brazillian manu.)PIO caps are all $4 or less.

Let's get this straight... first you suggest PIOs as the only way to go, then you're gonna go for the low buck PIOs? I'd just as soon source Vitamin Qs, Astron or Gudeman PIOs, if we're going high end we might as well go high end.

Those Russian caps are pretty impressive, too. They were meant to get a Mig through EMP from a nuclear blast without the avionics failing so I suppose they're good enough for my Champ!

And if you're breakin out that '40-something Chateau Lafite count me in for more than a cork sniff!

My "go to" plonk is usually something Australian and utilitarian. The good Bordeaux is worth at least a couple sets of NOS KT66s. The KT66s will still be around after dinner!

Now being a relative newb, I think the coupling caps are rated for the lower voltages, 25V verses 450V am I reading this right? Deluxe and Champ circuits.

Also if only the coupling are PIO would you mind sharing what you are using for the other Sprauge Atom? Illinois?

Oh no, don't do it! The coupling caps are a high voltage application, the 25 volt caps are cathode bypass caps. More is better voltage rating wise for coupling caps, 400 volts is good. Sometimes I'll stick in a 1000 volt or 1600 volt cap just because it's bigger and more impressive looking!

Illinois caps suck IMHO but that's just IMHO. Everyone is looking for something as good as Spragues without spending Sprague style money. Power supply caps aren't as critical as coupling caps because they're not in the signal path, all that matters is that they're big and juicy. Well, they shouldn't leak within the next ten years but we'll see in ten years, won't we?!

[Funkalicousgroove]

My favorite PIO's are only $5 ea, but they only sell them in Japan. I did complete my deluxe with the Mojo caps and it is Fantastic!

I didn't suggest PIO because I am snooty, I suggested them because the original Astron coupling caps in tweed fenders had a paper dielectric, and the PIO (cheap or expensive) sound closest to them.

I am not a proponent of silver solder, '0' AWG cable or any of the other audiophool stuff, I just find that tweed fenders sound closer to the real deal with PIO caps.


In my Deluxe I used T.A.D. filter caps, and I bypassed each one (16uf) with a .1uf 600v 6PS to drop the ESR, and i ended up adding another stage of filtering at the rectifier, and then a 3H choke before the OT center tap. No change in feel, but it eliminates all those ghost notes.

[CaseyJones]

My favorite PIO's are only $5 ea, but they only sell them in Japan. I did complete my deluxe with the Mojo caps and it is Fantastic!

I didn't suggest PIO because I am snooty, I suggested them because the original Astron coupling caps in tweed fenders had a paper dielectric, and the PIO (cheap or expensive) sound closest to them.

I am not a proponent of silver solder, '0' AWG cable or any of the other audiophool stuff, I just find that tweed fenders sound closer to the real deal with PIO caps.

The yellow Astron .022s can still be had for around $10.00 each. They seem to last nearly forever and stay on value which is more than I can say for the Astron electrolytics. Many of the Astron electrolytics are long dead with crusty white boogers growing out of them.

The high end parts debate is endless. Every other amp forum has the never ending threads on "Which tubes which transformers which resistors which capacitors which speakers" resulting in the full spectrum of subjective opinions. The usual conclusion is that for instance MM iron is the best and anything else is garbage or AB carbon comps are the only thing you can use or your amp will be junk. I just freakin' hate it when someone chimes in with an opinion like "PIOs are the only way to go" because the uninformed will read that without knowing why where or how and take it as gospel. Then some chucklehead sees a gutshot of my amp and disses it as total shite 'cuz that's what Funk said on The Forum. I dont't suppose that benefits any of us unless my amp really IS total shite... and it isn't.

[utervo]

Thanks a lot for the info.

My "local" (internet) store carries now those Vitamin T's. Perhaps I'll try them.

From there I can get carbon comps that are 1/2 Watt, I wonder if they can take it on the plates?

[skyboltone]

<snip>, and then a 3H choke before the OT center tap.

Whoa! That's one I haven't seen. Do you get some voltage drop over a direct connection?

Dan

[CaseyJones]

Thanks a lot for the info.

My "local" (internet) store carries now those Vitamin T's. Perhaps I'll try them.

From there I can get carbon comps that are 1/2 Watt, I wonder if they can take it on the plates?

The tweed Champ used 1/2 watt carbon comps throughout except for the 470 ohm bias resistor and the first 10k dropping resistor in the power supply. The plate resistors are half watt, they tend to drift up to around 140k but that's the nature of carbon comps. 1/2 watt is adequate. The 10k resistor in the power supply is "only" 1 watt. Metal oxides are compact so you can go two to five watts on the 10k and the 22k in the power supply.

The 1 watt 470 ohm cathode bias resistor on the 6V6 gets WARM at best. Original carbon comps are almost always discolored or drifted on original Champs. Use a three to five watt resistor there and you'll never have problems. 500 or 510 ohms is close enough. DO NOT mount the 25/25 cathode bypass cap in contact with the resistor. Under ideal conditions it may work, it's more typical that over time the heat from the 470 ohm resistor ruins the cap. Too much heat can short the cap, with the cap shorted the cathode connects straight to ground. Grounding the cathode on the 6V6 creates interesting fireworks inside the tube, if the 6V6 shorts it may take the OT with it. Bottom line: Leave space between the 25/25 cap and the 470 ohm resistor.